Here's what a blown apex seal sounds like. In case you don't know what a apex seal is...(Link to vid below)

The seal that goes on the corners of the rotor. It's purpose is to seal between the chambers of the rotor faces.

When it is blown. the seal will chip or crack and the seal between two chambers will lose their compression. Resulting in loss of performance dramatically. Another thing that happens commonly is the pieces that chip off are thrown around inside the engine; scraping, pitting, pretty much F***in the engine up real bad.

This can happen at anytime also. Some apex seals last for 250,xxx miles. while others will only last for a couple thousand.



http://youtube.com/watch?v=MN5WjN8SqA4

 

A couple thousand? Only if you rev or detonate the hell out of them.

 

Well it's been known to happen .I only stated the most extreme cases. 250,xxx is a very lucky engine. And a couple thousand miles leading to a busted seal is VERY unlikely but possible.